In recent years, research and development have been actively carried out regarding organic EL displays or organic EL lights that are light-emitting devices using an organic electroluminescence (EL) element. The organic EL element has a structure in which an organic layer, which is a thin film including an organic light-emitting material, is interposed between a pair of electrodes. The organic EL element is a self light-emitting element that uses light emission (fluorescence or phosphorescence) at the time of deactivation of excitons, which have been generated by recombination of holes and electrons injected into the thin film.
The most critical issue with the organic EL element is an improvement in the durability, and particularly, preventing non-light-emitting portions in the organic layer, which are called dark spots, from occurring and growing is the biggest issue. When the diameter of a dark spot grows to some tens of micrometers, non-light-emitting portions become visually observable. As a principal cause of the dark spots, the influence of moisture and oxygen is large, and it is known that moisture, even if in an extremely small amount, particularly exerts a large influence.
Therefore, methods for preventing moisture and oxygen from infiltrating into organic EL elements have been variously investigated. For example, in Patent Literature 1, a method involving providing a sealing layer composed of an inert liquid that contains an adsorbent around the circumference of an organic EL element in which an organic layer is laminated has been suggested.
Alternatively, for the purpose of physical protection of the organic layer, an improvement in the heat dissipation property and the like, a filled sealing structure in which an airtight container of the organic EL element is filled with a filler has been suggested, and additionally, a filled sealing structure that contains a drying agent as a filler also has been suggested. For example, in Patent Literature 2, a method involving using an organic metal compound that is a drying agent and has a predetermined structure together with a viscous substitution material such as silicone as filler has been suggested.